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Back To Normal Puget Sound Temps, But Air Quality To Fluctuate As Marine Air Surges In

Tim Durkan
Tim Durkan Photography
A return to skies like the one shown in this image from June 2016 is expected this weekend, but it may not last long.

A cloudy start to Friday with slightly cooler temperatures signaled a return to more normal conditions in the Puget Sound region after a week in which air quality reached its worst levels ever for a 24-hour period, measured by the particulate matter in the air.

But cool marine air was surging in as the weekend began, clearing out most of the smoke from wildfires, at least temporarily.

“The air quality is far better today,” said KNKX weather expert Cliff Mass on Friday. Mass is a professor of atmospheric sciences at the University of Washington.

“In fact, looking at the latest Puget Sound clean air statistics, the levels of particulates in the air – the small ones that get deep in your lungs – are about ten percent of what they were Wednesday. So, big improvement,” he said.

Mass says marine air began clearing things out on Thursday.

He expects Friday’s low clouds to break up later in the afternoon, with temperatures reaching the mid-70s.

“So, very normal temperatures…a very normal day,” Mass says.

Pleasant Weekend Ahead

Saturday, he says the weather will be roughly the same, with a few low clouds, temps in the 70s and air quality that “should still be pretty good.”

But he says it could get bad again, starting Sunday.

“High pressure is going to be building offshore and that’s going to set up more offshore flow – from the east and the northeast as we get into Sunday and Monday,” Mass said.

That will mean the likelihood of temps returning to the 80s, but also a probable decline in air quality.

“So it’ll be decent on Saturday. Sunday there will be a degradation. And I think it will even get worse on Monday,” he said.

Air Quality: ‘Up And Down’

“I don’t think it will get quite as bad we saw on Wednesday, but you’ll notice the haze starting to thicken in on Sunday, Monday and into Tuesday. “

“Later on in the week, an upper level trough comes through, marine air surges in and the air quality will improve again,” Mass said.

“So, up and down, that’s what we’re seeing.”

To hear the full conversation, including Cliff’s discussion of whether smokey summers are na new normal for the Pacific Northwest, you can click on the 'play' icon at the top of this post.

Weather with Cliff Mass airs at 9:02 a.m. Friday, right after BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KNKX environment reporter Bellamy Pailthorp. Cliff Mass is a University of Washington professor of atmospheric sciences, a renowned Seattle weather prognosticator, anda popular weather blogger. You can also subscribe to podcasts of Weather with Cliff Mass shows, viaiTunes or Google Play

Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to